Harry O
09-27-2006, 08:46 PM
I have what I have I been told is a Yankee mould that exactly matches the dimensions of a Lyman 358156 GC. It is made from brass and is a dream to cast with, just like the few other brass moulds I have. I have also found that this is a neat bullet to experiment with. The mould casts at between 0.359" and 0.360". I tried sizing and lubing some at 0.359", but it was a bit snug. 0.358" worked as slick as can be with the revolvers I planned to use.
I originally cast up a bunch of 40:1 lead over the gas check (for expansion) and accuracy was very good with mild loads, but pushing the load up, the accuracy went sour before I reached its limits. I cast up some more with a harder lead over the gas check and I was able to go as hot as I wanted to without any decrease in accuracy. I had an idea of chamber pressure vs Bhn needed without a gascheck, but I am now getting an idea of the relationship with a gascheck.
Recently, I tried switching the two bullet seating grooves. I can seat it in the lower groove in my .38 Specials and it still fits the K-frame S&W's nicely. Turns out that it is more accurate that way. So far, I have only used it that way with a mid-range (standard, not +P) load of 4.5gr of Unique, but it is the most accurate combination so far. Since there was more space between the bottom of the bullet and the top of the powder, I did not think that it would be as accurate as seating it deeper, but I was wrong. I think that the forward driving band is well within the cylinder throat, giving the bullet a straighter start into the forcing cone. I plan a number of other experiments with this bullet.
I originally cast up a bunch of 40:1 lead over the gas check (for expansion) and accuracy was very good with mild loads, but pushing the load up, the accuracy went sour before I reached its limits. I cast up some more with a harder lead over the gas check and I was able to go as hot as I wanted to without any decrease in accuracy. I had an idea of chamber pressure vs Bhn needed without a gascheck, but I am now getting an idea of the relationship with a gascheck.
Recently, I tried switching the two bullet seating grooves. I can seat it in the lower groove in my .38 Specials and it still fits the K-frame S&W's nicely. Turns out that it is more accurate that way. So far, I have only used it that way with a mid-range (standard, not +P) load of 4.5gr of Unique, but it is the most accurate combination so far. Since there was more space between the bottom of the bullet and the top of the powder, I did not think that it would be as accurate as seating it deeper, but I was wrong. I think that the forward driving band is well within the cylinder throat, giving the bullet a straighter start into the forcing cone. I plan a number of other experiments with this bullet.